The Myelodysplastic Syndromes (MDS) are an heterogeneous group of clonal disorders of the hematopoietic stem cell characterized by ineffective hematopoiesis leading to peripheral cytopenias, and variable risk of progression to more advanced disease and/or transformation to acute myeloid leukemia (AML). The disease affects predominantly elderly individuals (median age 69 years); the overall incidence is about 4 per 100,000 individuals but this rises to > 30 per 100,000 in the over 70 year age population.